Anoxic brain damage (ABD) is harm to the brain due to a lack of oxygen. Brain cells without enough oxygen will start to die after about four minutes.

Progression of Anoxic Brain Damage
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Oxygen is carried to the brain in the blood. ABD is when:

  • Blood flow is blocked or slowed. This can happen with:
  • The blood flow is normal, but the blood doesn’t have enough oxygen. This may happen if:
    • You have lung disease
    • There is a lack of oxygen in the air, which may happen at high altitudes
    • You have been around certain poisons, such as carbon monoxide
    • You have an event that is stopping you from breathing the right way, such as drowning, choking, or suffocation

Risk Factors

These problems may raise your chance of ABD:


ABD may cause:

  • Headache
  • Problems thinking
  • Problems focusing
  • Mood swings
  • Loss of consciousness
  • Seizures
  • Clumsiness
  • Coma
  • A decline in brain function days or weeks after the event (rare)


The doctor will ask about your symptoms and health history. A physical exam will be done. You may need to see a doctor with special training in brain problems.

These tests may be ordered to find out more about your brain problems:

  • Head CT scan
  • MRI scan
  • Electroencephalogram (EEG)—a test that measures the electricity in the brain
  • SPECT scans—a type of CT scan that looks at parts of the brain
  • Evoked potential tests—tests used to check your senses


Initial Treatment

Treatment will depend on the cause. It may mean:

  • Oxygen to raise the amount of oxygen in the blood
  • Medicine to help get enough blood with oxygen to the brain
  • Cooling the brain to limit problems


Recovery can take months or years. Whether you get better depends on how long you were without oxygen. Many people can get back most of the abilities they lost.

You and your family may work with a:

  • Physical therapist—to retrain motor skills, such as walking
  • Occupational therapist—to relearn daily skills, such as dressing and going to the bathroom
  • Speech therapist—to work on language problems
  • Psychologist—for behavior and emotional issues from the injury

Some people do not fully get better. They learn to cope with their disabilities. The sooner rehabilitation starts, the better the results.


To lower your chance of ABD:

  • Chew your food to avoid choking
  • Learn to swim
  • Supervise young children around water
  • Stay clear of high voltage electrical sources, including exposure to lightning
  • Avoid chemical toxins and illegal drugs
  • Install carbon monoxide detectors

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 05/2018 -
  • Update Date: 06/18/2018 -